1. Technical Field
The present invention relates to a magnetoencephalography meter and a neuromagnetism measuring method.
2. Description of the Related Art
In recent years, as a SQUID sensor-alternative high-sensitivity magnetometer, an optical pumping magnetometer using an alkali metal has been developed. Since the optical pumping magnetometer does not require a cooling function, and allows significant reduction in running cost against the SQUID sensor, the application to a magnetoencephalography meter or the like is expected.
In order to precisely measure a neuromagnetic field using the optical pumping magnetometer and to improve measurement sensitivity, multiple small optical pumping magnetometers should be used. Accordingly, for example, as described in P. D. D. Schwindt et al., “Chip-scale atomic magnetometer”, App. Phys. Lett. Vol. 85, No. 26, pp. 6409-6411 (2004), an optical pumping magnetometer having volume of 12 mm3 is produced by way of trial. The optical pumping magnetometer described in P. D. D. Schwindt et al., “Chip-scale atomic magnetometer”, App. Phys. Lett. Vol. 85, No. 26, pp. 6409-6411 (2004) has the following configuration. A vertical resonator surface light-emitting laser is provided at a position separated upward from a substrate, a vapor cell filled with rubidium vapor is provided below the vertical resonator surface light-emitting laser, and a photodiode is provided below the vapor cell. The photodiode is provided on the top surface of the substrate, and is configured to have a light receiving unit at a position where light emitted from the vertical resonator surface light-emitting laser and passed through the vapor cell is received.